If it's truly just a handful of people (five or less), this feels like it'd merit a face to face conversation. We're internet strangers making armchair assumpti

If it's truly just a handful of people (five or less), this feels like it'd merit a face to face conversation. We're internet strangers making armchair assumptions about other strangers, and it very well could be they have reasons for working beyond normal times. (Doesn't mean they're good reasons. But starting with a honest conversation, showing them evidence of working beyond the pale, and explaining why you're concerned about that should go a long way to untangling something deeper. Maybe they have a horrible home life they're wanting to distract themselves from, to which there are other solutions for.)